164 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Pea, Powdery Mildew. By J. M. Van Hook (U.S.A. E.rp. Stn. 

 Ohio, No. 173 ; April 1906). — This section of the report on pea blight is 

 devoted to the powdery mildew of the pea, Erysiphe communis. It is 

 ordinarily recognised by the whitish or greyish coating on all parts of 

 the pea plant, especially late in the season. The mildew fungus 

 lives over the winter on the seed. On account of the habits of the 

 powdery-mildew fungus it is easily prevented by applications of the 

 Bordeaux mixture. The vegetative part of the mildew fungus grows 

 mostly on the exterior of the host plant. Hence the fungicide is not 

 only a preventive, but actually kills the fungus in great part, when 

 sprayed upon it. On account of this manner of growing, many of the 

 powdery mildews are controlled by the use of sulphur alone. — M. C. C. 



Peas, Blighting of Field and Garden. By J. M. Van Hook 

 (U.S.A. Exp. Stn. Ohio, No. 173; with 12 figs.; April 1906).— This 

 report on blighting of peas is accentuated in interest by the assurance 

 that the blight is chiefly due to seed infection. The fungus causing 

 the disease is Ascochyta pisi (Lib.), well known as a pest in Europe. 

 Perhaps the most important feature is that the mycelium grows through 

 the husk of infected pods into the seed, and often produces spores there 

 by the time the peas are mature. More frequently the peas are mature 

 and dry before fruit bodies of the fungus develop, though discoloured 

 areas may appear. Seed treatment by immersion in liquid fungicides 

 failed to produce good results. Heating the seed also failed. Tying 

 up the plants and spraying increased the crop only slightly, but produced 

 peas much freer from this and other fungi. Planting such healthy peas 

 in soil free from the fungus is recommended as the best means of re- 

 ducing the loss from blight. — M. C. C. 



Peaches, Studies on. By W. D. Bigelow and H. C. Gore (U.S.A. 

 Dep. Agr. Bur. Chem., Bull. 97 ; 1905). — A review of the study of the 

 chemical analysis of peaches is followed by an account of the varieties 

 selected for analysis in this instance. Tables are given showing the 

 composition of the peaches at different stages of ripening and an account 

 of the changes which take place during the time the fruit may be kept in 

 cold storage. — F. J. C. 



Pears, Bergamot. By C. Maheut (Le Jardin, vol. xx. No. 465, 

 p. 199 ; July 5, 1906). — -The best of the sixty varieties of bergamot pears 

 are enumerated, with synonyms and various etymologies — from Bergamo 

 in Lombardy, Pergamus in Asia Minor, or from the Turkish beg and 

 armoudi, which signifies 'Pear of the Sovereign.' — F. A. W. 



Pear Blight. By R. E. Smith (U.S.A. Exp. Stn. California, Bull. 

 184 ; January 1907). — This virulent disease, which is due to the attacks 

 of a bacterium, has since 1904 (previous to which it was unknown in 

 California) been rife in various parts of the State, and by its attacks has 

 seriously threatened the pear-growing industry. Vigorous means are 

 being taken to combat it by the station staff acting with the central 

 government. Since the bacteria are carried from tree to tree by insects, 



